The influence of effective microorganisms (EM) and yeast on the degradation of strobilurins and carboxamides in leafy vegetables monitored by LC-MS/MS and health risk assessment

Nutritional compounds and risk assessment of mycotoxins in ecological and conventional nuts

This comprehensive study aimed to determine the level of nutritional compounds (20 amino acids, 11 phenolic acids, and 8 vitamins) and hazard compounds (14 mycotoxins) in ten types of conventional and ecological nuts from 25 countries. Moreover, chronic and acute toxicological risk assessment of mycotoxins was performed. Examined constituents were determined using LC-MS/MS. Ecological pine nuts showed the highest level of amino acids (233.87 g kg-1) compared to conventional (207 g kg-1), pecans-phenolic acids (816.6 mg kg-1 in ecological and 761 mg kg-1 in conventional), while pistachios-vitamins (3471.4 mg kg-1 in ecological and 3098.4 mg kg-1 in conventional). Increased concentration of mycotoxins was determined in conventional peanuts (54 μg kg-1) and walnuts (49.9 μg kg-1). Children were the most exposed population to acute intoxication with HT-2 toxin in conventional pistachios (20.66% ARfD). The results confirmed the nutritional importance of ecological nuts and emphasized the need for continuous screening of mycotoxins.

Pesticide residues in common and herbal teas combined with risk assessment and transfer to the infusion

The use of pesticides is permitted in tea cultivation, but many of them are withdrawn in Europe. The aim of this study was a comprehensive assessment of pesticide occurrence in common teas (black, green, red, white, and black flavored) and herbal teas (lemon balm and mint) and their transfer to the infusion. Among 603 pesticides, 24 were detected, of which 9 were withdrawn in Europe. Of the 64 tea samples, 47% had pesticide residues and 2% exceeded the European Maximum Residue Level (EU MRL; 572% for linuron/mint). The highest mean concentrations of the most common pesticides were 336 ng g-1 (quizalofop-P-ethyl/mint), 108.4 ng g-1 (MCPA/lemon balm), and 92.4 ng g-1 (glyphosate/red tea). A short time of brewing (5 min) had a higher transfer factor (TF) of most pesticides to the infusion (TF = 0.85/thiacloprid), compared to 30 min brewing (TF = 0.75/thiacloprid). Moreover, the physicochemical properties of detected pesticides, mainly density and melting temperature had a crucial impact on their transfer to the infusion. Acute risk was the highest for linuron/mint/children (17% of Acute Reference Dose; ARfD). Despite the withdrawal of some pesticides in the EU, they are still detected in tea samples. The results are pivotal for human health and highlight the need for further legislative action for tea.

Method development of multi pesticide residue analysis in country beans collected from Dhaka, Bangladesh, and their dietary risk assessment

The aim of the study was to develop a modified QuEChERS method coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of five multi-class pesticides in country beans collected from Dhaka, Bangladesh. Pesticides were extracted using ACN, and to minimize the co-extraction matrix, optimized d-SPE cleanup was done using sorbents (GCB, PSA, and C18). In the calibration range, the method showed excellent linearity with a correlation coefficient of R2 ≥ 0.9990 both in solvent- and matrix-matched calibration. For the selected pesticides, average recoveries (at four spiking levels (n = 5) of 10, 20, 100, and 200 µg/kg) of 70-100 % were achieved with relative standard deviations (RSDs) ≤ 9.5 %. The limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.3333 to 1.3333 μg/kg and 1.0 to 4.0 μg/kg, respectively. The dietary risk assessment, in terms of hazard quotient (HQ), was calculated to assess consumers' health risks.

Postinfection Application of Fenhexamid at Lower Doses in Conjunction with Captan Slowed Fungicide Resistance Selection in Botrytis cinerea on Detached Grape Berries

Fungicide resistance is a limiting factor in sustainable crop production. General resistance management strategies such as rotation and mixtures of fungicides with different modes of action have been proven to be effective in many studies, but guidance on fungicide dose or application timing for resistance management remains unclear or debatable. In this study, Botrytis cinerea and the high-risk fungicide fenhexamid were used to determine the effects of fungicide dose, mixing partner, and application timing on resistance selection across varied frequencies of resistance via detached fruit assays. The results were largely consistent with the recent modeling studies that favored the use of the lowest effective fungicide dose for improved resistance management. In addition, even 10% resistant B. cinerea in the population led to about a 40% reduction of fenhexamid efficacy. Overall, our findings show that application of doses less than the fungicide label dose, mixture with the low-risk fungicide captan, and application postinfection seem to be the most effective management strategies in our controlled experimental settings. This somewhat contradicts the previous assumption that preventative sprays help resistance management.

Effect of Three Commercial Formulations Containing Effective Microorganisms (EM) on Diflufenican and Flurochloridone Degradation in Soil

The aim of this study was to determine the influence of effective microorganisms (EM) present in biological formulations improving soil quality on degradation of two herbicides, diflufenican and flurochloridone. Three commercially available formulations containing EM were used: a formulation containing Bifidobacterium, Lactobacillus, Lactococcus, Streptococcus, Bacillus, and Rhodopseudomonas bacteria and the yeast Saccharomyces cerevisiae; a formulation containing Streptomyces, Pseudomonas, Bacillus, Rhodococcus, Cellulomonas, Arthrobacter, Paenibacillusa, and Pseudonocardia bacteria; and a formulation containing eight strains of Bacillus bacteria, B. megaterium, B. amyloliquefaciens, B. pumilus, B. licheniformis, B. coagulans, B. laterosporus, B. mucilaginosus, and B. polymyxa. It was demonstrated that those formulations influenced degradation of herbicides. All studied formulations containing EM reduced the diflufenican degradation level, from 35.5% to 38%, due to an increased acidity of the soil environment and increased durability of that substance at lower pH levels. In the case of flurochloridone, all studied EM formulations increased degradation of that active substance by 19.3% to 31.2% at the most. For control samples, equations describing kinetics of diflufenican and flurochloridone elimination were plotted, and a time of the half-life of these substances in laboratory conditions was calculated, amounting to 25.7 for diflufenican and 22.4 for flurochloridone.

Biochemical compounds and stress markers in lettuce upon exposure to pathogenic Botrytis cinerea and fungicides inhibiting oxidative phosphorylation

MAIN CONCLUSION

Botrytis cinerea and fungicides interacted and influenced selected biochemical compounds. DPPH and glutathione are the first line of defence against biotic/abiotic stress. Plant metabolites are correlated with fungicides level during dissipation. Botrytis cinerea is an etiological agent of gray mould in leafy vegetables and is combated by fungicides. Fluazinam and azoxystrobin are commonly used fungicides, which inhibit oxidative phosphorylation in fungi. In this study, lettuce was (i) inoculated with B. cinerea; (ii) sprayed with azoxystrobin or fluazinam; (iii) inoculated with B. cinerea and sprayed with fungicides. This investigation confirmed that B. cinerea and fungicides affected lettuce's biochemistry and stress status. B. cinerea influenced the behaviour of fungicides reflected by shortened dissipation of azoxystrobin compared to non-inoculated plants, while prolonged degradation of fluazinam. Stress caused by B. cinerea combined with fungicides reduced level of chlorophylls (53.46%) and carotenoids (75.42%), whereas increased phenolic compounds (81%), ascorbate concentrations (32.4%), and catalase activity (116.1%). Abiotic stress caused by fungicides contributed most to the induction of carotenoids (107.68 µg g-1 on dissipation day 3-1). Diphenyl picrylhydrazyl (DPPH) radical scavenging activity and glutathione concentration peaked from the first hour of fungicides dissipation. For the first time correlation between the status of plant metabolites and fungicides during their dissipation was observed. These results indicate that non-enzymatic antioxidants could be the first-line compounds against stress factors, whereas ascorbate and antioxidant enzymes tend to mitigate stress only secondarily. The findings of this study help better understand plant biochemistry under biotic/abiotic stress conditions.

Dissipation kinetics and processing behavior of boscalid and pyraclostrobin in greenhouse dill plant (Anethum graveolens L.) and soil

BACKGROUND

Determining the environmental behavior and fate of chemical compounds during technological processing of plants is a task of great significance nowadays. However, the current knowledge is still incomplete for unique herbal matrices belonging to minor crops. The research in this article presents, for the first time, the dissipation kinetics and processing behavior of carboxamide boscalid (BOS) and stobilurin pyraclostrobin (PYR) fungicides during glasshouse dill (Anethum graveolens L.) cultivation.

RESULTS

The half-lives (t_1/2 ) of BOS and PYR after application at the recommended and double dosage were in the range: 1.62-2.01 days in plant and 2.08-4.85 days in soil, respectively. The processing behavior in dill was estimated after washing, hot air drying and drying in sunlight without/with pretreatment. Processing factors (PFs) were above 1 after drying (PF = 1.24-1.39 hot air; PF = 1.15-1.28 sunlight) and below this value when the washing step was applied (PF = 0.31-0.42 hot air; PF = 0.21-0.34 sunlight), indicating the highest effectiveness of reduction, up to 73% BOS and 79% PYR.

CONCLUSION

BOS/PYR residues at pre-harvest intervals after both doses were below European Union (EU) maximum residue limits (MRLs). The highest effectiveness was noted for drying carried out with the washing step, which has a great influence on the concentration of residues in the final product. The findings can supplement PF databases not set for minor crops and can be used to establish MRLs and determine human exposures more accurately in risk assessment studies. © 2021 Society of Chemical Industry.

Dissipation kinetics and biological degradation by yeast and dietary risk assessment of fluxapyroxad in apples

The aim of this study was to investigate the dissipation kinetics of fluxapyroxad in apples, the influence of biological treatment with yeast, and the estimation of dietary exposure for consumers, both adults and children. The gas chromatography technique with the electron capture detector was used to analyse the fluxapyroxad residues. Samples of apples were prepared by the quick, easy, cheap, effective, rugged and safe (QuEChERS) method. The average fluxapyroxad recoveries in apple samples ranged from 107.9 to 118.4%, the relative standard deviations ranged from 4.2 to 4.7%, and the limit of quantification was 0.005 mg/kg. The dissipation half-lives in Gala and Idared varieties were 8.9 and 9.0 days, respectively. Degradation levels of the tested active substance after application of yeast included in a biological preparation Myco-Sin were 59.9% for Gala and 43.8% for Idared. The estimated dietary risk for fluxapyroxad in apples was on the acceptable safety level (below 9.8% for children and 1.9% for adults) and does not pose a danger to the health of consumers.

Uptake, translocation and accumulation of the fungicide benzene kresoxim-methyl in Chinese flowering cabbage (Brassica campastris var. parachinensis) and water spinach (Ipomoea aquatica)

Benzene kresoxim-methyl (BKM) is an important methoxyacrylate-based strobilurin fungicide widely used against various phytopathogenic fungi in crops. Uptake, translocation and accumulation of BKM in vegetables remain unknown. This study was designed to investigate uptake, translocation, and accumulation of ¹⁴C-BKM and/or its potential metabolites in Chinese flowering cabbage and water spinach. ¹⁴C-BKM can be gradually taken up to reach a maximum of 44.4% of the applied amount by Chinese flowering cabbage and 34.6% by water spinach at 32 d after application. The ¹⁴CO₂ fractions released from the hydroponic plant system reached 37.8% for cabbage and 45.8% for water spinach, respectively. Concentrations of ¹⁴C in leaves, stems and roots all gradually increased as vegetables growing, with relative 44.9% (cabbage) and 26.8% (water spinach) of translocated from roots to edible leaves. In addition, ¹⁴C in leaves was mainly accumulated in the bottom leaves, which was visualized by quantitative radioautographic imaging. The bioconcentration factor of ¹⁴C ranged from 7.1 to 38.2 mL g^-1 for the cabbage and from 8.6 to 24.6 mL g^-1 for the water spinach. The translocation factor of BKM ranged from 0.10 to 2.04 for the cabbage and 0.10-0.46 for the water spinach throughout the whole cultivation period, indicating that the cabbage is easier to translocate BKM from roots to leaves and stems than water spinach. In addition, the daily human exposure values of BKM in both vegetables were much lower than the limited dose of 0.15 mg day^-1. The results help assess potential accumulation of BMK in vegetables and potential risk.

Cichoric acid attenuates the toxicity of mesotrione. Effect on in vitro skin cell model

There is an important need to increase knowledge regarding the interactions between environmental contaminants and other compounds. Pesticides are an important group of food contaminants. By contrast, cichoric acid (CA) belongs to the category of desirable food ingredients with antioxidant and cytotoxic effects. The aim of the presented study was to test if CA may constitute a food ingredient, which eliminate stimulatory effect of pesticides on skin cancer cells and toxic effect of herbicides on fibroblasts. Therefore, we conducted cytotoxicity studies of environmentally relevant pesticide concentrations and the mixture of both compounds in melanoma and fibroblasts cells. We studied if CA combined with mesotrione change the oxidative stress parameters and apoptotic activity in treated cells. Obtained results indicate that CA exhibits cytotoxic activity against mesotrione-induced skin cancer development by influencing oxidative stress parameters and apoptosis. On the other hand CA inhibits prooxidative and proapoptotic activity of mesotrione in fibroblasts. Presented methods and obtained results could be a useful tool in the analysis of environmental contaminants toxicity and possible preventive activity of antioxidative plant- origin compounds.

Influence of a Commercial Biological Fungicide containing Trichoderma harzianum Rifai T-22 on Dissipation Kinetics and Degradation of Five Herbicides in Two Types of Soil

Biological crop protection is recommended to be applied alternately or together with chemical one, to protect human health from the excessive use of toxic pesticides. Presence of microorganisms can influence the concentration of chemical pollutants in soil. The aim of this study is to estimate the influence of a commercial biological fungicide containing Trichoderma harzianum Rifai T-22 on dissipation kinetics and degradation of five herbicides belonging to different chemical classes: clomazone, fluazifop-P-butyl, metribuzin, pendimethalin, and propyzamide, in two types of soil. Results of the study revealed that T. harzianum T-22 influences pesticide degradation and dissipation kinetics of the non-persistent herbicides: clomazone, fluazifop-P-butyl, and metribuzin. In soil with a higher content of nitrogen, phosphorus, and organic matter, degradation increased by up to 24.2%, 24.8%, and 23.5% for clomazone, fluazifop-P-butyl, and metribuzin, respectively. In soil with lower organic content, degradation was on a low level, of 16.1%, 17.7%, and 16.3% for clomazone, fluazifop-P-butyl, and metribuzin, respectively. In our study, the addition of the biological preparation shortened herbicide dissipation half-lives, from 0.3 days (2.9%) for fluazifop-P-butyl, to 18.4 days (25.1%) for clomazone. During the degradation study, no significant differences were noticed for pendimethalin, belonging to persistent substances. Biological protection of crops can modify pesticide concentrations and dissipation rates. On one hand, this may result in the reduced effectiveness of herbicide treatments, while on the other, it can become a tool for achieving cleaner environment.

Dissipation pattern and residual levels of boscalid in cucumber and soil using liquid chromatography-tandem mass spectrometry

To stipulate the rationale of spraying doses and to determine the safe interval period of boscalid suspension concentrate (SC), the degradation dynamics and residual levels were investigated in cucumber and soil using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Field trials were conducted according to Chinese Guideline on pesticide residue trials. Following application, the degradation kinetics was best ascribed to first-order kinetic models with half-life of 2.67-9.90 d in cucumber. Spraying boscalid SC at 1.5-fold the recommended dosage yield terminal residues, which are clearly lower than the maximum residue limit (MRL) established by China (MRL =5 mg.kg^-1) in cucumber. At variance, the dissipation dynamics in soil did not fit to first-order kinetics and the half-life was more than 17 days, the finding which denotes that the degradation behavior of boscalid in soil proceeds slowly. It has therefore been shown that boscalid is safe for use on cucumbers under the recommended dosage.

Assessment of boscalid and pyraclostrobin disappearance and behavior following application of effective microorganisms on apples

The aim of this study is to assess the disappearance of boscalid (IUPAC name: 2-chloro-N-[2-(4-chlorophenyl)phenyl]pyridine-3-carboxamide) and pyraclostrobin (IUPAC name: methyl N-[2-[[1-(4-chlorophenyl)pyrazol-3-yl]oxymethyl]phenyl]-N-methoxycarbamate) residues in apple fruit, and to verify whether an organic fertilizer enriched with strains of antagonistic microorganisms can reduce pesticide residue levels. Field trials were conducted in a commercial orchard on apples of the Gloster variety, during 21 days after the treatment with Bellis 38 WG and the subsequent application of Zumba Plant formulation containing Bacillus spp., Trichoderma spp. and Glomus spp. In control samples, the decrease rate of boscalid and pyraclostrobin residue levels followed an exponential function, described by formulae R_t = 0.2824e^-0.071t and R_t = 0.1176e^-0.060t, with the coefficient of determination of r² = 0.8692 and r² = 0.9268, respectively. These levels dropped to half (t_1/2) of their initial values after 9.8 and 11.5 days, respectively. The treatment with Zumba Plant resulted in a reduction in boscalid and pyraclostrobin residue levels by 52% and 41%, respectively. The results of this study are of importance for horticulture sciences and for producers of apples using plant protection products (PPPs).

Dissipation behavior of octachlorodipropyl ether residues during tea planting and brewing process

The dissipation behavior of octachlorodipropyl ether (OCDPE) residues in fresh tea shoots and in tea prepared under field conditions was investigated, and the transfer of residues from brewed tea to tea infusion was determined. OCDPE levels in tea shoots, prepared tea, tea infusion, and spent tea leaves were determined using a sensitive and simple method. The dissipation of OCDPE is fairly slow in tea shoots and prepared tea, with half-life values of 5.10 and 5.46 days, respectively. The degradation rates of OCDPE residues in tea processing were 23.9-43.1 %. The terminal residues of OCDPE in tea shoots and prepared tea samples after 20 and 30 days of OCDPE application were higher than 0.01 mg/kg. However, OCDPE's transfer rates from brewed tea to tea infusion were only 6.0-14.8 %. Further studies on risk assessment of OCDPE residue in tea on the basis of the relationship of OCDPE in prepared tea and infusion are warranted.